Accurate measurement techniques and prediction approaches for the in-situ rock stress.

The precise calculation and evaluation of the in-situ rock stress tensor is a crucial factor in addressing the major challenges related to subsurface engineering applications and earth science research. To improve the accuracy of in-situ stress measurement and prediction, an improved overcoring technique involving a measurement circuit, temperature compensation, and calculation method is presented for accurately measuring the in-situ rock stress tensor. Furthermore, an embedded grey BP neural network (GM-BPNN) model is established for predicting in-situ rock stress values.

Comparison and evaluation of overcoring and hydraulic fracturing stress measurements.

The stress measurements determined by both the overcoring (OC) and hydraulic fracturing (HF) methods in the Shuichang iron mine and Sanshandao gold mine were compared and evaluated, respectively. The results indicate that the independent OC and HF data in the two mines reveal the same dominant faulting stress regime. The σ orientations derived from the OC and HF methods in the Shuichang iron mine are dominantly oriented in the N81.